Design on the Ef-126 "Lilli" began in late
1944, as part of the "Jager-Notprogramm". It was planned on
paper to make two version, one powered by a Argus As 044 pulse-jet engine
(Ef-126) and one powered by a Walter rocket engine (Ef-127) little work
was done on ether aircraft by the time the Soviets occupied the Dessau
plant in 1945, apart of the building of a wind tunnel model and a mockup
of the Ef-126, no construction was undertaken.

The Ef-126 was to have been made up of a metal fuselage
with wooden wings, with as much as possible being made from low grade
and recycled non-strategic materials.

However under Soviets occupations, construction
of a prototype Ef-126 was started in October 1945 at the Dessau plant,
with a full scale mockup being ready by January 1946, the Soviets were
impressed enough to order the Junkers team to make five aircraft. The
first prototype was completed by mid May 1946, with it's first flight
soon after wards, flown by Matthies. The aircraft was not fitted with
an engine at this point, but was towed* into the air by a Junkers Ju-88G.
The second test flight was on the 21/5/1946, this again with out the Argus
As 044 engine being fitted, this flight ended with the aircraft crashing
and killing the pilot Herr Matthies.

Another view of the same Ef-126

The wind tunnel model in 1945

After the crash a number of modifications were made to the
design of the other four aircraft. In the summer of 1946 a Soviet commission
inspected the work of the Junkers staff and in September 1946 three aircraft
the V-2,V-3 and V-4 were transferred to the USSR for further flight trials
and tests, the V-5 remained in Germany at the Dessau works, it having it's
first flight on the 16/3/1947 again towed into the air by a Ju-88.

But by the 20/6/1948, it was decided by the Soviet Aviation
Ministry that all work on the Ef-126 should be stopped in Germany and the
USSR.